1. Field of the Invention
The present invention relates to a liquid crystal display device and, specifically, to a technology which is effectively used to control the coating area of an alignment layer.
2. Description of the Related Art
A liquid crystal display device includes a pair of transparent substrates sandwiching liquid crystals as a housing, and the liquid crystals are sealed by a seal material which also serves to fix the pair of the transparent substrates. The area surrounded by this seal material constitutes an effective display area (also simply referred to as “display area”) in which pixels as constituent elements of the liquid crystal display device are arranged in a matrix. The each pixel has a thin film transistor and is independently driven by, for example, active matrix drive system so that the pixels can display an image in the effective display area.
An alignment layer is formed on a surface in direct contact with the liquid crystals of each of the transparent substrates of the liquid crystal display device constituted as described above. This alignment layer is to orient the molecules of the liquid crystals in a certain direction (initial orientation direction) and is formed by orienting a resin film formed by coating. In this case, it is desired that the alignment layer should be formed in such a manner that a certain distance is kept between its peripheral end and the seal material. This is because the reliability of the sealing function of the seal material deteriorates when the alignment layer is formed into the formation area of the seal material.
Meanwhile, it is desired that a liquid crystal display device which is incorporated into a personal digital assistance such as a cell phone should have as large a display area as possible with its small external size (the so-called frame size should be small), and therefore the separation distance between the seal material and the alignment layer cannot be made sufficiently large. Therefore, there is known a liquid crystal display device including a linear transparent conductive film layer made of ITO (Indium Tin Oxide) which surrounds the alignment layer in the area between the seal material and the alignment layer. This transparent conductive film layer functions as a stopper (may be referred to as “alignment layer stopper” hereinafter) which prevents a resin film before curing from flowing into the formation area of the seal material when the alignment layer is formed. The reason that the alignment layer stopper is formed of a transparent conductive film is that the alignment layer stopper is formed of the same layer as a pixel transparent electrode and can be formed simultaneously with the formation of the pixel electrode. An example of the liquid crystal display device constituted as described above is a liquid crystal display device disclosed by Japanese Unexamined Patent Application No. 2010-8444.